Fretting wear study on Ti-Ca-P biocomposite in dry and simulated body fluid

In the present work, powder metallurgy processing was used to synthesize a titanium rich composite containing in situ formed bioactive calcium-phosphatic phases. The potential application of such a composite includes load-bearing implants. In view of the importance of friction and wear in biomedical applications, the present work was taken up to investigate the friction and wear properties of such Ti-Ca-P composite at fretting contact against bearing steel in simulated body fluid (SBF) environment. A comparison was also made with fretting behaviour in dry conditions. Tribological experiments were carried out on a biocomposite against bearing steel at different loads (2, 5 and 10 N) for 10,000 cycles with displacement stroke set to 80 mu m and at 10Hz frequency using a low amplitude reciprocatory fretting wear tester. In addition to reporting the measured tribological data, a major focus of the work was in understanding dominant wear mechanisms under dry ambient and physiological environment. (c) 200

Availability and suitability of agroindustrial residues as feedstock for cellulose-based materials: Brazil case study

Bio-based polymers have emerged as a feasible alternative to petrochemical polymers mainly due to their biodegradability and renewable feedstock. Brazil is considered one of the largest producers of agricultural commodities. Hence, the country is also distinguished by the large generation of this residue type, which can be potentially used as a source to obtain biopolymers, such as cellulose. Based on the Brazil agriculture market, the study aims to analyze the suitability of agroindustrial residues as raw material for cellulose-based materials. A methodology for the selection of the most suitable residues is proposed, which takes into account the chemical composition of residues, namely the cellulose content and the cellulose-to-lignin ratio, as well as, their availability. In order to meet conservation issues, the availability of residues is calculated as a function of sustainable removal rates and competitive uses. Taking as reference the main crops identified, the average amount of agroindustrial residues available in Brazil was estimated at 108 million tons/year. Among the most suitable residues to be used as cellulose feedstock are soybean straw, sugarcane top/leaves, maize husk and stover and sugarcane bagasse.This work was supported by the Brazilian National Council for Scientific and Technological Development (Grant Number 201940/2015-9)